Reducing valve



:7 26, i%& F. TQHARRINGTON v fi REDUCING VALVE Filed Nov. 16, 1937INVENTOR. fie/ 7* @W /g/k a ro/ ATTORNEY.

to provide spring backed' reducing valves.

. Patented Dem 26, 1939 9 Claims. 'This invention relates to a reducingvalve and has particularly to do with a reducing valve whichvalvehousing but in a valve which was quite subject to chattering action.Because of this chattering action it has been impossible to design areducing valvewhich was capable of accurate a djustment and regulation.

The object of the present invention is to provide spring -may be usedand in which the overall size maybe about one-third that of the ordinaryreducingvalve. A further object of the invention is to provide areducing valve in which chattering .has been eliminated and whichprovides. a more closely defined pressure regulation.

Briefly this has been accomplished by establishing a pressure regulatorchamber behind the valve piston and connecting this chamber through arestricted passageway with the low pressure chamber of the valve andalso through an adjustable check valve to a tank outlet. By reason ofaslight flow or leakage from the low pressure chamber through thisrestricted passageway to the pressure regulating chamber, the pressurein the low pressure chamber is not permitted to build up -above anadjustment or setting of the check valve. The pressure in the regulatingchamber also forms a load on the valve piston and this hydraulic loadcooperates with the spring behind the piston to permit an accurateregulation of the reducing pressure.

In the drawing the single figure'is a longitudinal cross-section throughthe .valve housing, the fluid passageways being shown in one plane forpurposes of illustration.

Referring to the drawing, there is shown an embodiment of the inventionwhich has been seiected for purposes of d sclosure. This embodiment iscomposed of a main housing i, an end cap 2 and a pressure controlhousing 3.: The main housing l is provided with a longitudinalcylindrical recess in which is slidably disposed, a valve piston 8 whichwill later b'e described. A

- spring 5 seated in the housing 3 urges the valve piston ti toward anabutment 6 on the end cap 2.

The housing 9 has a pressure inlet port '8 which enters the centralpiston recess in the. housing and forms an annular port 8 around thepiston i. A pressure outlet chamber 9 bounded on one side by the end cap2 is formed in the housing a reducing valve in which a comparativelylight t sin s PATENT O F Ferris T. Harrington, Detroit. Mich., assignorto Vickers, Incorporated, Detroit, poration of Michigan hpplicationNovember16, 193'l,\Se1-ialNo. 174,858

1 tissue Mich., a corg l and is open to a pressure outlet port 10., Theport '8' and the chamber 9 communicate through a restriction orpassageway l I in the housing I. This restriction forms a. part of therecess for the valve piston 4 and also forms a valve seat iz adapted tocooperate with-a portion of the valve piston 4.- The pressure outletchamber 9 is connected'to a balance chamber I3 through a passageway 14in which is located a restriction pin-I5, a portion of which has a crosssection' very slightly smaller than the passageway I4.

The valve piston 4 has a slender rod portion l6 adapted to be positionedsubstantially within I the restriction II and at theend of which is apiston formation I! having a diameter larger than that of the passageII. This piston il has. a beveled portion I8 adapted to close the valveseat llwhen in contact therewith. When in its open position the pistonI1 is held against the *abutment 6 by reason of the action of'the spring5. 20 The housing 3 has a passageway l9 which opens at one end to thebalance chamber l3 in the housing 4 and which opens at the other endthrough a spring-pressed, adjustable check valve 20 to a tank outlet 2|.i

In the operation, the pressure in the balance chamber I3 is the same asthat in the outlet chamber 9' and in the inlet recess 8 until thepressure exceeds the setting of the check valve 20.- At this point thecheck valve bypasses a sufficient volume from the balance-chamber I3 tocause a pressure drop. In view of the fact that the passageway i8 isrestricted the pressure drop in the balance chamber 83 will permitthepressure acting on the piston l! in the outlet chamber 9 to .move thevalve piston t against the spring 5 I thereby closing the communicatingpassage or restriction ll between the inlet recess 8 and the outletchamber 9.

in the ,closed position the piston d is hydraulically balanced intheinlet recess 8 because of the fact that the seating area exposed inthe communicating passage ii is the same as the area of the pistonplunger 8. The piston d is held in this closed or restricted positiondue to the pressure difirential between the outlet chamber 9 and thebalance chamber l3. when the pressure in the balance chamber l3 dropsbelow the setting of'the pressure control of the check 50 valve 20,causing it-to close, the fluid flows from outlet chamber 9 through therestricted passage way i4 and increases the pressure in the balancechamber 63 to that in the outlet chamber 9.

' Under these conditions the spring 5 returns the g5 areas at each-endof the piston are equal.

In the actual operation of the valve an equilibrium is established andthere is analmostconstant leakage from the low pressure chamber 9through the restriction I! to the regulating chamber l3. This slightleakage keeps the pressure from building up in chamber 8 and also formsa leakage load'on the top of the piston I.

Any tendency for the pressure to build up in the chambers 9 and I3 abovethe setting of the check valve is overcome by the opening of the checkvalve at which time the leakage load in the ton ll to close or partiallyclose the passageway ll.

The pressure control valve 20 may be adJusted to open at. any desiredpressure.

balance chamber l3 will regulate the pressure maintained in the outletchamber 9 regardless of the pressure in the inlet port 8. A smoothacting reducing valve is thereby provided. The amount of restriction inthe passageway M will, of course,

have to be regulated to correspond with the viscosity of the fluidnormally used in the system.

What I claim is:

1. In an adjustable fluidi pressure reducing sageway independent of saidpiston valve between said outlet chamber and saidpressure chamber, and apressure relief valve connecting said. piessure chamber with a tankoutlet.

' 2. In an adjustable fluid pressure reducing valve, a housing providedwith inlet and outlet chambers, a piston valve between said chambers,means tending normally to hold said valve .open, said housing having apressure chamber behind said valve and a restricted passagewayindependent) of said piston valve between said outlet chamber and saidpressure chamber, and a pressure relief valve connecting said pressurechamber with a tank outlet.

3. In an adjustable fluid pressure reducing valve of the type having aclosely flttedspring pressed piston and the usual inlet and outletchambers,

an additional housing providing'a pressure chamber behind the piston anda restricted passageway between the outlet chamber and said pressurechamber, and a relief valve in a passageway leading from said pressurechamber to a tank outlet and. adapted to open at a predeterminedpressure whereby a predetermined pressure may be maintained in saidoutlet chamber irrespective of changes in said inlet chamber.

66 4. In an adjustable fluid pressure reducing valve of the type havinga housing and a closely fitted spring pressed piston and the usual inletand outlet chambers, an additional housing portion providing a pressurechamber on the spring 6!? side of the piston and a restricted passagewaybetween the outlet chamber and said pressure chamber, and an adjustablepressure actuated relief valve opening from said pressure chamber to atank outlet.

' chamber, an outlet chamber connected therechamber I3 is slightlyreduced to permit the pis- Thus, controlling of the pressure or leakageload in the 5. An adjustable fluid pressure reducing valve chamber.

comprising housing portions having an inlet with,-a pressure regulatingchamber, and a restricted passageway between said last two chambers, avalve piston slidably disposed in said housing and adaptedfin oneposition, to close the inlet and outlet chambers from each other, arelatively light spring acting normally to hold said valve piston open,and an adjustable, spring pressed relief valve opening from saidpressure,-

regulator chamber to a tank outlet whereby a predeterminedv pressure maybe maintained in said outlet chamber.

6. An adjustable fluid pressure reducing valve comprising housingportions having an inlet chamber, an outlet chamber connected therewith;

. chamber and acting on said piston to open said valve, and an'adjustable, spring pressed relief valve o'pening from said pressureregulator chamber to a tank outlet whereby a predetermined reducedpressure may be maintained in said outlet chamber irrespective ofpressure changes in said inlet chamber.

7. In an adjustable fluid pressure reducing valve of the type having aclosely fitted spring pressed piston and the usual low pressure and highpressure chambers, an additional housing providing a regulating pressurechamber behind pressure chamber and said regulating pressure chamber, arestriction in said passageway and a relief valveopening from saidpressure chamber to a tank outlet whereby the control unit utilizes theleak from the low pressure chamber to keep pressure from building uptherein.

8. In an adjustable fluid pressure reducing valve of the type. having 'aclosely .fltted spring pressed piston and the usual low pressure andhigh pressure chambers, an additional housing providing a regulatingpressure chamber behind the piston and a passageway between the lowpressure chamber and'said regulating pressure chamber, a restriction. insaid passageway and a relief valve opening from said pressure chamber toa tank outlet whereby the control unit utilizes the leak from the lowpressure chamber to keep pressure from building up therein and to form a.controlled hydraulic load for governing the reduced pressure.

9.. In an adjustable fluid pressure reducing valve of the type having aclosely fltted spring pressed, substantially balanced piston and theusual low pressure and high pressure chambers,

- outlet, and a restriction in said passageway to utilize the leak fromthe low pressure chamber to form a controlled hydraulic load on saidpiston for governing the reduced pressure whereby a constantpredetermined reduced pressure may be maintained in said low pressurechamber irrespective ot changes in 'r. mammal.

said high pressure the piston and a passageway between the low

